We've stayed in Gerardmer a few times, and here twice:
Hotel Au Petit Boulas
4, place du Tilleul
GERARDMER
Tél : 03 29 27 10 06
Fax : 03 29 27 11 91
Can't find a website. It was clean, cheap, did unfussy but very nice grub, and had a secure garage behind the hotel for parking the bikes. It was not at all modern! In fact, a typical French hotel, all non-matching furniture and enormous room keys.
It is a great biking area, and I don't know why more people don't rave about it. The higher passes are fairly high, though. Last time I was there was in mid-May and while the roads were clear, there was still serious snow on the ground in the mountains and it was bloody freezing!
There are enough roads to fill three or four days of gentle exploring without too much retracing of steps. Gerardmer is pretty central and everywhere is accessible from there in a day. There are no bad roads!
I've never really explored Gerardmer or any of the towns in the area, although a quick trip round the lake is pleasant enough. The roads themselves are just great, though. The Route des Cretes is a good north-south ride, but zig-zagging east and west will cover more of the roads. Col de la Schluct is always fun but gets very busy with bikes on a sunny weekend - not sure if that's a good thing or a bad thing. The car park and bar at the top gets very busy, but it makes for a pleasant half hour wandering looking at the bikes. You can also go on the dry toboggan chute thing but that looks too scary and dangerous to me.
Col du Bonhomme was being widened last time I was there. Hopefully this means it'll now be like a race track! Some of the minor roads across the mountains are pretty twisty, though - ideal for a GS. The road tunnel at St Marie aux Mines is closed now, I believe, but the equivalent pass to St Marie was one of my favourites.
If you have time, a trip across to Germany and around parts of the Black Forest is worth it and maked for a good (if slightly long) day trip. The road to Marckolsheim on the Rhine flood plain is so wide, smooth and straight that it it impossible not to cane it before you cross over the river. At Riegel in Germany is the brewery that makes Reigler beer - you have to have one as you have your sausage and chips in a little cafe.
Try this as a round trip: Gerardmer, Ribeauville, Marckolsheim, Riegel, Elsbach, Schonwald, Furtwangen, Titisee, Todtnau, Badenweiler, Guebwiller, Gerardmer. 7-odd hours riding, add in two or three hours for meals and a coffee, and I reckon that's as good a day's road riding as you'll get!
Enjoy your trip. When are you going?